JP3203267B2 - Ion accelerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ion accelerator.

[0002]

2. Description of the Related Art FIGS. 3 to 5 show a conventional ion accelerator. In these figures, a high voltage terminal 42 is provided in a ground shield box 41 with a predetermined voltage higher than the ground level. It is supported on an insulating support plate 46 provided at the ground level by four insulating supports 45. An intermediate terminal 47 is wound around these insulating posts 45 by equally dividing the distance from the high voltage terminal 42 to the ground level, and the high voltage terminal 4 is interposed between them.
A resistor 48 is connected between the second and intermediate terminals 47 or the insulating support plate 46.

A power supply device 50 is provided beside the high voltage terminal 42, and its upper end is connected to the high voltage terminal 42 by a power cable shield pipe 57. This conventional power supply device 5
Numeral 0 is a so-called insulating transformer, a commercial power supply is connected to the primary side, the secondary side extends upward, and the upper end thereof covers the corona shield 56.

Further, a stack for high-voltage power supply (high-voltage power supply of Cockloft-Walton type) 51 is provided on the side of the power supply device 50, and the output terminal of the oscillator 52 is connected to the lower end of this stack via a cable. Connected. The Cockloft-Walton type high-voltage power supply device 51 is configured in a known manner, and has a configuration in which diodes, capacitors, and the like are coupled stepwise as shown in FIG. As you go upward, the pressure is increased,
In this conventional example, a maximum voltage of 400 KV is obtained, and the upper end is covered with a corona shield 54, which is connected to the high voltage terminal 42 by a contact rod 55.

In the high voltage terminal 42, an ion source 43 having a known structure, a mass separation magnet 44, a power source 66 for plasma generation, a power source 67 for drawing out, a gas box 68 and the like are arranged. An acceleration tube 60 is connected to one side wall, and a focusing Q lens 61, an XY scanning unit 62, and an injection chamber 63 are provided in connection with the acceleration tube 60. One end of the acceleration tube 60 is at the same level as the ground shield box 41. An exhaust pipe 49 is connected between the other side wall of the high-voltage terminal 42 and the ground shield box 41 and connected to the external vacuum pump 12.

FIG. 6 shows the details of the power supply device 50 described above. Commercial power is supplied to the input terminals U and V of the primary winding of the lower transformer section 50b. The boosted voltage obtained from the secondary winding is supplied to the ion source 43, the mass separation magnet 44, and the like via the electrodes U 'and V' at the upper end of the conductor 50a extending upward and long. Is what you do. The conductor 50a is covered with the bushing 50c made of an insulating material as described above.

The details of the high voltage generator 51 are shown in FIG. 7. In this device 51 as well, the lower part is a transformer 51b, and the input terminals p and q rectify the commercial frequency. 20KHz with switching circuit
The reduced high frequency is connected, and the secondary winding is configured in a cascade, and is connected to the voltage doubler 51a which is a connection of the diode D and the capacitor C as shown. A high voltage of 400 KV is obtained at the upper end.

The conventional ion accelerator is constructed and operates as described above. As clearly shown in FIG. 4, an accelerating tube 60 is provided on the right side in the drawing of the high voltage terminal 42 with a shield box 41. And an exhaust pipe 49 is connected to the shield box 41 on the left side. An ion beam is led out from the ion source 43 and is bent by the mass separation magnet 44 toward the acceleration tube 60 in the figure. However, the ion source 43 and the acceleration tube 60 Cannot be arranged on the same straight line. Exhaust pipe 49 and acceleration pipe 6
0 is attached to the left and right side surfaces of the high-voltage terminal 42, which increases the volume of the shield box 41 that electromagnetically shields the high-voltage terminal 42.

[0009] In order to temporarily reduce this, the acceleration tube 60
When the exhaust pipe 49 is connected between the same side of the high-voltage terminal 42 and the shield box 41 in FIG. 4, the size of the exhaust pipe in the high-voltage terminal 42 with respect to the vacuum pump 12 becomes longer, and the conductance becomes smaller. Becomes
The pressure of the ion source 43 cannot be reduced to a predetermined degree of vacuum.

X-rays generated in the accelerating tube 60 (which are generated by secondary ions generated by accelerating ions ionizing residual gas in the accelerating tube or colliding with an electrode) are ground shield box 41. Prevents leakage to the outside. Further, the corona shields 54 and 56 have a spherical shape with a certain curvature or more in order not to generate corona discharge.

Further, between the intermediate terminals 47 or between the intermediate terminals 47 and the high-voltage terminals 42 or the insulating support plate 4
Between the high voltage terminals 4
2 and the ground level are equally divided potentials. As a result, electric field disturbances and ion beam fluctuations (load fluctuations) caused by charging of the intermediate terminals and the insulator surface
Even if the electric field is disturbed due to fluctuations in the voltage generated due to
The probability of discharging is reduced, and the voltage can be stably generated for a long time.

[0012]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and can reduce the total volume of a casing to which a high voltage is applied, that is, a shield box for electromagnetically shielding a high voltage terminal. It is intended to provide an ion accelerator.

[0013]

In order to solve the problems described above purpose, the ground
At least at the ion source and mass
One side of a casing containing a separating magnet and the casing
And one side of a shield box for electromagnetically shielding
A) each accelerating tube and b)
An exhaust pipe of an exhaust device for exhausting the ON source;
For applying the voltage of the voltage power supply to the casing.
A first bushing in which an electric member is covered with an insulating material;
Supply power to the ion source and the mass separation magnet
A second bushing in which a conductive member for leading out is covered with an insulating material
And a pair of the other side surface of the casing and the other side surface.
Between the inner wall surface of the shield box facing
The exhaust pipe is connected only to the ion source.
A vacuum pump provided in a continuous exhaust passage,
Inside a container fixed to the outer wall of the box and filled with insulating fluid
A high-voltage generating unit of the high-voltage power supply device arranged in the unit;
The ion accelerator characterized in that it comprises a power generating unit, a power supply device, is accomplished by.

[0014]

An accelerating pipe, an exhaust pipe of an exhaust device, and an insulating material covering a conductive member for leading predetermined power of a power supply device are provided between one side surface of a casing to which a high voltage is applied and an inner wall surface of a shield box. The first bushing and the high voltage generator are covered with a conductive member for deriving a high voltage, and the second bushing made of an insulating material is connected and fixed. Therefore, the distance between these surfaces and the inner wall of the opposing shield box can be connected with some insulating material to obtain a withstand voltage of the atmosphere larger than the withstand voltage determined by creeping discharge. These distances can be made much smaller than before, so that one side of the casing or high voltage terminal and the inside of the shielding box Considering only the creeping discharge disposed an insulated material between the well and therefore the total volume of the shielding box can be greatly in small. For example, when 400 KV is applied to the high voltage terminal or the casing, a normal withstand voltage distance to the inner wall of the shield box is required to be 80 cm to 1 m. Since it is insulated only from the inside of the box with the inner wall of the box, 50-60
Clearly, the total volume of the shield box can be significantly smaller, as it can be measured in cm. In addition, the height of the pillar that supports the high-voltage terminal on the ground is the same as before.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an ion accelerator according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view of the entire ion accelerator of this embodiment. In FIG. 1, a high-voltage terminal 1 is provided in a shield box 2. As in the conventional case, the ion source 3, the extraction electrode 4, the plasma generating material gas storage box 6, the power supply 5 for plasma generation, and the like are built in the high voltage terminal 1 (these arrangements are slightly different from the conventional ones). A mass separation magnet 44 is connected to the ion source 3 in the same manner as in the prior art.
Is connected to the accelerating tube 60. This one end is connected to the shield box 2.

According to the present invention, the first vacuum pump 7 is connected to the ion source 3, and the second vacuum pump 9 is connected to the conduit 8. A third vacuum pump 12 is provided outside the shield box 2,
This is connected to a T-shaped exhaust duct 10 via an exhaust pipe 11. This is connected to the first vacuum pump 7,
It further assists a second vacuum pump 9 connected to the conduit 8. Further, a fourth vacuum pump 40 is attached to the focusing Q lens unit 61 to exhaust the inside of the acceleration tube 60.

Further, according to the present invention, the insulating transformer 14, the transformer section 14a of the high voltage generator 16 and the high voltage generator 16a are disposed outside the shield box 2, and the shield box 2 and the high voltage terminal 1 In order to connect the high voltage of the insulating transformer 14 and the high voltage generator 16 to the high voltage terminal 1 between the shield box 2 and the high voltage terminal 1, Connected between Where
The other bushing 13 corresponds to the second bushing according to the present invention.
And the other bushing 15 is the first bushing according to the present invention.
To respond to

The details of the high-voltage generator 16 are shown in FIG. 2. The insulating container 16b of the high-voltage generator 16a is fixed to the outer wall surface of the shield box 2 , and
Insulating oil M is filled as an insulating fluid.
The highest voltage section of 6A is connected to the high voltage terminal 1 via a resistor 16B. In FIG. 2, the output terminals of the oscillator are connected to the input terminals a and b of the voltage doubler circuit section 16A.

The transformer section 14a of the insulating transformer 14 includes a metal container 14b, which is also a shield box 2.
Is fixed to the outer wall surface of the motor , and is filled with insulating oil M in the same manner as the high-voltage generating device 16, and a transformer section including the primary coil C ₁ , the iron core F, and the secondary coil C _{2 in the} insulating oil M Is immersed. Deriving terminal e from the secondary side coil C _2, f extends upwardly, from which the high-voltage terminal 1 within the ion source 3, a mass separation magnet 44, for supplying power to such extraction electrode 4. The high-voltage generating device 16 is fixed to the shield box 2 as described above, and a bushing 20 made of an insulating material is attached between the shield box 2 and the high-voltage terminal 1. The highest voltage of the voltage generator 16 is connected to the resistor 16B, but covers it. Also bushing 2
At 0, metal rings 21 are attached at predetermined intervals, and these are connected by a resistor 22.

[0021] Between the secondary side coil C ₂ side is extended to the high-voltage terminal 1 side, the high voltage terminal 1 bushing 23 and shield box 2 made of an insulating material so as to surround this isolation transformer 14 A metal ring 24 is fixed at a predetermined interval on the outer periphery, similarly to the high-voltage generator 16, and is connected by a resistor 25 between the metal rings 24.

Similarly, the outer circumferences of the exhaust pipe 11 and the acceleration pipe 60 are covered with bushings 26 and 29 made of an insulating material, and metal rings 27 and 30 are fixed to the outer circumference at predetermined intervals. Between these two resistors
8 and 31 are connected. m is a metal ring fixed around the opening formed in the terminal 1 for preventing discharge.

An ion accelerator according to an embodiment of the present invention
The configuration is as described above. Next, this operation will be described.

The first and second vacuum pumps 7 and 9 reduce the pressure of the conduit 8 connected to the ion source 3 and the mass separation magnet 44 to a predetermined pressure. An exhaust pipe 1 is provided by a third vacuum pump 12 disposed outside the shield box 2.
1 and the exhaust pipe 11 and the mass separation magnet 44 through the exhaust duct 10 to assist the first and second vacuum pumps 7 and 9.
The inside of the conduit 8 connecting the gas and the acceleration pipe 60 is evacuated so as to reduce the pressure to a predetermined pressure reduction degree.

In the above state, ions accelerated from the ion source 3 at a predetermined voltage in the same manner as in the prior art are mass-separated by the mass separation magnet 44, and only predetermined ions are passed through the conduit 8 and the acceleration tube 60. It is led to the ion implantation device 63.

The operation of this embodiment is as described above, but has the following effects. That is, as is apparent from FIG. 1, according to the present embodiment, the accelerating pipe 60, the exhaust pipe 11, the bushing 13 of the insulating transformer 14, and the bushing 15 of the high voltage generator 16 are provided on one side of the high voltage terminal 1.
Since all are mounted, no devices are mounted on the other three sides, and thus the high voltage terminal 1 is, according to this embodiment, applied with 400 KV, Only the atmosphere is interposed between the other side and the shield box 2, and if the distance is the same, the withstand voltage is higher than when the side of the high-voltage terminal 1 and the shield box 2 are connected with an insulating material. Is much larger in the former. Therefore, in order to obtain a predetermined withstand voltage, the distance between the shield box 2 and the side surface of the high voltage terminal 1 can be further reduced, and the acceleration tube 60, the exhaust tube 11, the bushing 13 of the insulating transformer 14, the high voltage generation The distance between the side surface of the device 16 where the bushing 15 is mounted and the inner wall of the shield box 2 facing this can be made much smaller. Therefore, the total volume of the shield box 2 surrounding the high voltage terminal 1 can be made much smaller. Therefore, the cost of the present ion accelerator can be significantly reduced. Compared to other equipment of this type, which generally requires a larger occupation area, the occupied area can be greatly reduced, so that limited factory area can be used effectively. can do. Further, in the above embodiments, the metal rings 21, 24, 27,
30 are mounted with resistors 22, 25, 2
Since the electrodes 8 and 31 are provided, an equipotential surface as indicated by the line L is formed evenly between the shield box 2 and the high-voltage terminal 1 to stably maintain a high voltage.

Although the embodiment of the present invention has been described above, the present invention is not limited to this, and various modifications can be made based on the technical concept of the present invention.

[0028] For example, in the above embodiment, but the high voltage generator 16 and the insulating vessel of the insulating transformer 14 is filled with insulating oil M as a medium for insulation, instead of this, SF ₆
May be filled with an insulating gas such as

[0029]

As described above, according to the ion accelerator of the present invention, the total volume of the high voltage terminal, that is, the shield box for shielding the casing to which the high voltage is applied is made much smaller than that of the conventional ion accelerator. The cost and the area occupied by the ion accelerator can be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a plan view of an ion accelerator according to an embodiment of the present invention.

FIG. 2 is a plan view showing the relevant part in an enlarged cross section.

FIG. 3 is a front view of a conventional ion accelerator.

FIG. 4 is a plan view of the same.

FIG. 5 is a side view of the same .

FIG. 6 is a partially enlarged side sectional view of the device.

FIG. 7 is an enlarged side sectional view of another part of the device.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 high voltage terminal 2 shield box 3 ion source 7 first vacuum pump 9 second vacuum pump 10 exhaust duct 11 exhaust pipe 12 third vacuum pump 13 bushing (second bushing) 14 insulating transformer 15 bushing (first bushing) ) 16 High voltage generator 60 Accelerator tube

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-60-158400 (JP, A) JP-A-5-29095 (JP, A) JP-A-5-266995 (JP, A) JP-A-1- 311556 (JP, A) JP-A-59-187281 (JP, A) JP-A 60-138249 (JP, U) JP-A 62-193600 (JP, U) JP-A 62-58900 (JP, U) Special Table Hei 1-500942 (JP, A) (58) Fields surveyed (Int. Cl. ⁷ , DB name) H05H 5/02

Claims (2)

(57) [Claims] (1) The apparatus is provided at a predetermined height from the ground, and
Of the casing containing the ion source and mass separation magnet
A shield bore for electromagnetically shielding one side and the casing
A ) an accelerating tube, respectively; b) an exhaust pipe of an exhaust device for exhausting the ion source.
If, a voltage of c) a high voltage power supply to said casing
A first bushing in which a conductive member is coated with an insulating material, and d) power of a power supply device is supplied to the ion source and the mass.
The conductive member for leading to the demagnetized magnet is covered with an insulating material.
2 bushing, and the other side of the casing and the sheet facing the other side.
Only the atmosphere is interposed between the inner wall of the box and
And provided in an exhaust passage connecting the exhaust pipe and the ion source.
Vacuum pump and filled with insulating fluid fixed on the outer wall of the shield box
Height of the high-voltage power supply placed inside the
Ion accelerator characterized by having a a power generation unit of the voltage generator and the power supply device. 2. The high-voltage power supply and the power supply are Cockloft-Walton type and insulation transformers, respectively, and their stack units and transformer units are respectively located in containers filled with the insulation fluid. Item 2. The ion accelerator according to Item 1.